A basal rate profile defines basal rate delivery for a selected time interval. It can have a pre-defined number of profile segments each defining the basal rate delivery for a subset of the selected time interval (i.e., a so-called time interval subset). The basal rate profile may also be defined by a steady mathematical function. In this case, each profile segment can correspond to a specific value of the mathematical function. The time interval subsets can then correspond to the time instances associated with the values of the mathematical function. Hence, the expression “profile segment” can also refer to a single value of a basal rate profile and the expression “time interval subset” or “subset of the selected time interval” can also refer to a single time instance of the selected time interval.
A basal rate profile for an insulin pump can comprise basal rate values for 24 hours, i.e. basal rate values for an entire day. In the case of diabetes, the basal rate defines a low rate of continuous insulin supply/delivery needed for controlling cellular glucose and amino acid uptake. The basal rate can be given in the unit IU/h (international unit per hour). The expression “basal rate profile” according to the present specification is also used for a part/time segment of another basal rate profile, e.g. of a 24-hour basal rate profile, that is stored in an insulin pump.
However, programming and changing of basal rates can require the manipulation of all profile segments of a stored basal rate profile. For example, if the selected time interval is 24 hours and the subset of the selected time interval is 1 hour, then there are 24 profile segments. If the subset of the selected time interval is 30 minutes, then there are 48 profile segments. Having to manipulate all profile segments thus might lead to high programming effort that can be reduced by defining less profile segments which, however, might lead to simpler, blockier basal rate profiles and decreased preciseness of medical treatment. Furthermore, the start basal rate and the end basal rate of a 24-hour basal rate profile may not be adjusted such, that an immediate repetition of the same basal rate profile, for example at midnight, might entail an unintentional jump in the basal rate delivery.
In some methods for setting basal rates for an implantable insulin pump, the delivery rates need not be entered for each subset of the selected interval of time, but only for those subsets that represent a change in delivery rate compared to a previous subset. In these methods, the selected time interval can be 24 hours beginning at midnight and the subset of the selected time interval can be 30 minutes. Hence, each set of basal rates would consist of 48 rates that can start on any half-hour of the day.
With some computer software (e.g., “ACCU-CHEK Insulin Pump Configuration Software Pro”), a 24-hour basal rate profile with 24 profile segments can be set by either inputting all 24 basal rate values required for the 24 profile segments into the personal computer via a keyboard and typing in the values, or by pressing scroll buttons with respect to the values for all profile segments, or even by pressing a mouse button, moving the mouse (thereby moving a cursor) and then releasing the mouse button, thereby increasing or decreasing bars with a cursor such that each bar represents a profile segment. The personal computer on which the software is installed can be connected to an insulin pump.
Furthermore, a basal rate profile can be set by defining a number of supporting points for the basal rate profile via an input unit of an insulin pump, generating a continuous function in accordance with the supporting points by means of a calculation unit of the insulin pump, and generating a time sequence of basal rates from the continuous function by the calculation unit.
Therefore, a need exists for alternative methods and apparatuses for setting a basal rate profile for an insulin pump